Under certain circumstances, particularly in a frontal impact event, some vehicles tend to rise. While the degree of rise of a vehicle may vary according to vehicle type, the rise is itself a common phenomenon. In such a situation an unbelted occupant tends to move vehicle forward toward the front of the seat. This is so because no belt is in use that would otherwise restrict forward movement. In addition, because a deployed airbag ordinarily presses against either the front or the side of the occupant and thus prevents the unbelted occupant from moving further forward, the vehicle rise can push an unbelted occupant upward inside the vehicle compartment.
Particularly, and according to known seat designs in today's vehicles, the rise of the vehicle in a frontal impact event results in a number of potential challenges to the unbelted seat occupant. A main concern is, if the seated occupant is unbelted, the head of the driver or of the front seat passenger may contact the roof, the visor, the headliner or the windshield during a frontal impact event.
Since the current seat design is constrained to be adjustable for all different impact modes, it may be that an adjustable seat pan height can significantly enhance unbelted occupant safety protection, in addition to the optimized restraints system. However, current seat designs do not permit for the adjustment of seat pan height in an impact event.
As in so many areas of vehicle technology, there is always room for improvement related to improving the safety of unbelted seat occupants in vehicles in an impact event.